Manufacturing solid calcium nitrate



Patented Dec. 8, I 1925.

CARL EYER AND ROBERT GRIESS BACH,

MANY, ASSIGNORS T0 BADISCHE ANILIN- PATENT OFFICE.

OF LUDWIGSHAFEN-ON-THE-RHINE, GER- & SODA FABBIK, OF LUDWIGSHAFEN- ON-THKRHINE, GERMANY, A CORPORATION'OF GERMIANY.

MANUFACTURING SOL ID CALCIUM NITRATE.

' R'o Drawing.

T 0 all whom it may concern:

Be it known that we, CARL EYER and ROBERT GRIESSBAOH, citizens of the German Empire, residing at Ludwigshafen-on-the Rhine, Germany, have invented new and useful Improvements in Manufacturing Solid Calcium Nitrate, of which the following is a specification.

Our present invention relates to a process of manufacturing solid calcium nitrate. It is known that hot highly concentrated calcium nitrate solutions solidify slowly and with difficulty by reason of very viscous undercooled products being first formed. Even when solid product is added to initiate crystallization the process of solidification is still too slow for practical purposes.

We have made the surprising and important practical discovery that a solid product can be readily obtained from concentrated calcium nitrate solutions containing a small amount of an ammonium salt. The amount may vary within certain 'limits but-should not, as a rule, exceed about 2 percent calculated as NH in the mixture (or about 12 percent of ammonium nitrate) and preferably ranges between about 0.3 and 0.9 percent NH (or about 1.7 and 5 percent of ammonium nitrate). The ammonium is added most suitably in the form of nitrate, but sulfate or other ammonium salts may also be added, orcompounds, such as urea,

which are converted into ammonium compounds by the'action of hot concentrated calcium .nitrate.

Calcium nitrate solutions of the character described excel owing to their property of freezing rapidly at comparatively high temperatures, and solidification may accordingly be carried out in any known or suitable manner. The liquid mass may be stirred in a cooling pan until solid, or it may be brought, in a thin layer, onto a cooled re volving drum and solidification takes place even rapidly enough to employ s raying of the solution in, or with the aid, 0 a current of air or other gas.

The stability of the product is not unfavorably influenced by the said additions while on the other hand the roduct has the advantage of an increased nitrogen content. s

For example, a calcium nitrate solution Application filed June 29, l925. Serial No. 40,449.

evaporated to a strength of about 70 degrees Baum is mixed with about 5 percent its weight of ammonium nitrate whereupon the mixture is cooled while stirring. Freezing begins at as high as about 70 degrees centigrade, when the mass first grows crumbly and then fully solidifies on further cooling. An addition of particles of solid mass may be of some assistance, but generally it is not necessary. Pure calcium nitrate solution, free from ammonium salt, would begin to solidify at as low as degrees centigrade only, under similar conditions. Again when such solution is sprayed by means of com pressed air the drops of the spray will fall downin a-liquid state, while with an addition of about 2 or 3 per cent of ammonium nitrate to the hot solution of 70 degrees Baum, a solid product in the form of globular little grains like solidified drops or spray of liquid suitable for spreading is at once obtained.

Or, a calcium -nitrate solution of 1.985 specific gravity is mined with 5 percent its weight of ammonium chlorid and cooled While stirring. The mass begins to crumble at between about 90 and 95 degrees centigrade and solidifying is soon complete. This mixture may also be solidified bythe spraying method.

What we claim is:

1. The process of manufacturing solid calcium nitrate, which consists in cooling a hot concentrated calcium nitrate solution containing a moderate content of ammonium salt.

2. The process of manufacturing solid calcium nitrate, which consists in cooling a hot concentrated calcium nitrate solution containing an amount ofammonium salt equal to less than 10 percent of ammonium nitrate.

3. The rocess of manufacturing solid calcium nitrate, which consists in spraying, by means of a current of air, a hot concentrated solution of calcium nitrate colntaining a small amount of ammonium sa t.

4. As a new article of manufacture, solid calcium nitrate containing in molecular distribution a small amount of an ammonium salt.

5. As a new article of manufacture, calcium nitrate containing in molecular dise ual to less than 10 per cent of ammonium tribution an amount of ammonium salt nitrate and having the form of globular equal to less than 10 per cent of ammonium little grains like solidifieddrops of liquid. 10

nitrate. In testimony whereof we have hereunto 6. As a new article of manufacture, 091- set our hands. cium nitrate containing in molecular dis- 7 CARL EYER.

tribution an amount of ammonium salt ROBERT GRIESSBACH. 

